The Role of Immunohistochemical Markers (P63 and TTF-1) in the Diagnosis and Classification of Non-Small Cell Lung Carcinoma

Abstract

BACKGROUND Lung carcinoma is the most common cause of cancer mortality worldwide. Most non-small cell lung carcinomas are inoperable and histologic diagnosis made on small biopsy samples are prone to diagnostic inaccuracy. So, precise subtyping of poorly differentiated non-small cell lung carcinoma (NSCLC) into adenocarcinoma and squamous cell carcinoma has a direct impact on management of patient and prognosis. The aim of this study was to investigate the role of immunohistochemistry profile using p63 and TTF-1 for differentiating nonsmall cell lung carcinoma into squamous cell carcinoma and adenocarcinoma. MATERIALS AND METHODS This descriptive study was conducted to assess p63 and TTF-1 expression in 80 cases of non-small cell lung carcinoma received in the Department of Pathology, Government Medical College, Kottayam during a period of 18 months (March 2016-September 2017). RESULTS Present study includes 80 cases of histologically diagnosed NSCLC. Of the study population, 73 cases (91.25%) were males and 7 cases (8.75%) were females. Among males, squamous cell carcinoma is the predominant histological subtype and adenocarcinoma is the predominant subtype in females. In this study, peak incidence is between 60-69 years of age. The mean age is 61 years. Out of the 80 histologically diagnosed cases of NSCLC studied, after IHC confirmation 47 were squamous cell carcinoma (58.75%), 27 were adenocarcinoma (38.75%), 3 were adenosquamous (3.75%) and rest 3 were NSCLC-NOS (3.75%). Histologically diagnosed cases of squamous cell carcinoma show 100% positivity for p63 and adenocarcinoma shows 100% positivity for TTF-1. CONCLUSION Both p63 and TTF-1 have 100% expression in squamous cell carcinoma and adenocarcinoma respectively. Hence, these markers may be recommended for subtyping of poorly differentiated non-small cell lung carcinoma (NSCLC).